THE CASSIN VIREO. . 365 
box, a rattling, rubbing, shaking note, of three or more vibrations, ending 
in a little vocal flourish. 
These Vireos swing a bulky basket from the lower or middle heights 
of oak trees, fir trees, alders, or saplings of various sorts. Usually no 
dependence is placed in cover, save that the ornamented nest corresponds 
roughly with its general surroundings of leaf, moss and lichen. In shel- 
tered places, the texture of the nest is so well preserved that it may 
require close inspection the second season to distinguish it from a new 
nest. One such I examined, green with growing moss, and stark at the 
lowermost branch-tip of an 
y unleafed cornel sapling, and 
I could not have determined 
its age save for a tiny weed- 
shoot germinating from the 
bottom of the cup. 
Further Mr. Bowles 
says of their nesting 
habits: ‘Both birds 
assist in the duties of 
incubation, the male 
singing most  assidu- 
ously while on the 
nest, and usually sing- 
ing close to his mate 
while she is sitting. 
His turn at sitting 
; seems to come be- 
Taken near Tacoma. Photo by Bowles and Dawson tween nine o’clock in 
A DECORATED NEST. the morning and noon, 
and the nest is not 
hard to find if his song can be traced. The bird student must work 
quietly, however, as the song at once ceases should any unusual noise 
occur. They are most courageous while on the nest, seldom leaving until 
removed by hand, when both birds remain within a few feet of the 
intruder, scolding vigorously. So much noise do they make that all 
the birds in the vicinity are attracted—indeed this is about the only sure 
method of ascertaining the presence of some of our rarer Warblers. 
On one such occasion a female Cooper Hawk left her nest, which was 
seventy-five yards distant, and sat on a branch overhead, screaming 
at me. 
“They are the quickest as well as the slowest birds in com- 
pleting their nests that have come under my notice. One pair built a 
